Double fire stapling

ABSTRACT

A tool assembly for a surgical stapling instrument includes anvil and cartridge assemblies movable between open and closed positions. The cartridge assembly includes a cartridge body defining a tissue contact surface and rows of staples. The cartridge body defines a first firing channel associated with a first row of staples and a second firing channel associated with a second row of staples. A firing cam is positioned within the first firing channel and translates therethrough during a first axial translation to fire the first row of staples. The first firing cam is biased to move into the second firing channel upon retraction after the first axial translation such that the first firing cam translates through the second firing channel upon a second axial translation to fire the second row of staples.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/927,675, filed Oct. 30, 2015, which claims the benefit of andpriority to U.S. Provisional Patent Application Ser. No. 62/119,354,filed Feb. 23, 2015, the entire disclosure of which is incorporated byreference herein.

TECHNICAL FIELD

The present disclosure relates to surgical stapling apparatus, devicesand/or systems for performing endoscopic surgical procedures and methodsof use thereof.

BACKGROUND

Surgical stapling apparatus that clamp, cut and/or staple tissue betweenopposing jaw structure are well known in the art. Such surgical staplingapparatus can include loading units with a tool assembly having twoelongated jaw members used to capture or clamp tissue. One of the twojaw members usually carries a staple cartridge that houses a pluralityof staples while the other of the two jaw members has an anvil forforming the staples as the staples are driven from the staple cartridge.Generally, a stapling operation is effectuated by a cam bar, a drivesled or other similar mechanism having a cam member that travelslongitudinally through channels defined in the staple cartridge and actsupon staple pushers in the channels to sequentially eject the staplesfrom the staple cartridge.

During endoscopic or laparoscopic procedures in which surgery isperformed through small incisions or through narrow cannulas insertedthrough the small incisions in the skin, replacement of the staplecartridge or the loading unit, for example, after firing, requiresremoval of the surgical stapling device from the incision or cannula,replacement of the staple cartridge and/or loading unit and reinsertionof the surgical stapling device into the incision or cannula.

It would be advantageous to provide a staple cartridge or loading unitthat is capable of being fired a plurality of times before replacementof the staple cartridge or loading unit is required.

SUMMARY

Accordingly, the present disclosure is directed to a surgical staplingapparatus for use during laparoscopic and/or endoscopic surgicalprocedures that can be employed to provide multiple firings of thesurgical stapling apparatus without requiring removal of the surgicalstapling apparatus from the incision/cannula. In particular, the presentdisclosure is directed to a tool assembly, loading unit, and/or asurgical stapling apparatus that includes a firing cam assembly with oneor more firing cams. The firing cam assembly is positioned to repeatedlymove longitudinally through a staple cartridge to effectuate multiplefirings with each firing cam during longitudinal translations of thefiring cam assembly from a proximal end to a distal end of the staplecartridge. The firing cam assembly may include a knife bar configured tocut tissue as the firing cam assembly longitudinally translates throughthe staple cartridge. Advantageously, the firing cam assembly can befired multiple times without removing the surgical stapling apparatusfrom an in vivo work space before the staple cartridge and/or theloading unit would require changing/reload, greatly reducing time tocomplete the in vivo surgical procedure.

In one aspect, the surgical stapling device of the present disclosureincludes a housing, a shaft that extends distally from the housing, anda tool assembly supported on the shaft. The tool assembly may include acartridge assembly, an anvil assembly, and a first firing cam.

The cartridge assembly has a cartridge body that may define a tissuecontact surface and a plurality of rows of retention slots. Eachretention slot of the plurality of rows of retention slots supports astaple therein and defines an opening on the tissue contact surface. Thecartridge body defines a first firing channel and a second firingchannel. The first firing channel is associated with a first row ofstaples and the second firing channel associated with a second row ofstaples.

The anvil assembly is supported adjacent the cartridge assembly. Theanvil assembly and the cartridge assembly are movable between open andclosed positions in relation to each other.

The first firing cam is positioned within the first firing channel ofthe cartridge body. The first firing cam is configured to translatethrough the first firing channel during a first axial translation of thefirst firing cam to fire the first row of staples. The first firing camis biased to move into the second firing channel of the cartridge bodyupon retraction of the first firing cam after the first axialtranslation such that the first firing cam moves to a position totranslate through the second firing channel upon a second axialtranslation of the first firing cam to fire the second row of staples.

The first firing cam may be engaged with a first T-bar. The first T-barmay be positioned to maintain the first firing cam in registration withthe first firing channel when the first firing cam and the first T-barare in fully retracted positions.

In some embodiments, the tool assembly includes a second firing cam andthe cartridge body defines third and fourth firing channels. The secondfiring cam is configured to translate through the third firing channelduring the first axial translation to fire a third row of staples. Thesecond firing cam is biased to move into the fourth firing channel uponretraction of the second firing cam after the first axial translationsuch that the second firing cam is positioned to translate through thefourth firing channel upon the second axial translation to fire a fourthrow of staples.

The second firing cam may be engaged with a second T-bar. The secondT-bar may be positioned to maintain the second firing cam inregistration with the third firing channel when the second firing camand the second T-bar are in fully retracted positions.

The first and second T-bars are configured to move along the cartridgebody in response to movement of the first and second firing cams from aproximal position to a distal position during the first axialtranslation. The first and second T-bars are retained in the distalposition as the first and firing cams are retracted to the proximalposition after the first axial translation. In the distal position, thefirst and second T-bars are positioned to enable movement of the firstand second firing cams. The first and second firing cams may bepivotally coupled together and positioned to pivot relative to oneanother.

In certain embodiments, the cartridge body defines a T-bar recess. Thefirst and second T-bars are positioned within the T-bar recess while thefirst and second T-bars are disposed in the distal position.

In some embodiments, the cartridge body includes a first ramp and asecond ramp. The first ramp is positioned to align the first firing camwith one of the first and second firing channels. The second ramp ispositioned to align the second firing cam with one of the third andfourth firing channels.

The tool assembly may further include a knife bar that supports a bladeat a distal end of the knife bar. The cartridge body defines a knifechannel. The knife bar is distally movable through the knife channel asthe first firing cam translates through the first and second firingchannels.

In some embodiments, the first firing cam includes a cam surfacepositioned to engage a plurality of pusher members. Each of theplurality of pusher members is disposed within one or more of theretention slots and is configured to support one or more of the staples.The cam surface of the first firing cam may extend distally beyond theblade of the knife bar.

In certain embodiments, the cartridge body defines a knife channeltherethrough. Two of the first, second, third, and fourth firingchannels may be disposed on one side of the knife channel and aremaining two of the first, second, third and fourth firing channels aredisposed on another side of the knife channel.

Other aspects, features, and advantages will be apparent from thedescription, the drawings, and the claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosureand, together with a general description of the disclosure given above,and the detailed description of the embodiment(s) given below, serve toexplain the principles of the disclosure, wherein:

FIG. 1A is a perspective view of a surgical stapling apparatus inaccordance with the principles of the present disclosure;

FIG. 1B is a perspective view, with parts separated, of the surgicalstapling apparatus of FIG. 1A;

FIGS. 2 and 3 are side, perspective views of a loading unit of thesurgical stapling apparatus of FIG. 1A;

FIG. 4 is a perspective view, with parts separated, of the loading unitof FIGS. 2 and 3;

FIG. 5 is a perspective view, with parts separated, of a cartridgeassembly of the loading unit of FIGS. 2-4;

FIG. 6 is a perspective view of a firing cam assembly of the loadingunit of FIGS. 2-4;

FIG. 7 is an enlarged perspective view of an indicated area of detailshown in FIG. 6,

FIG. 8 is a top view of the firing cam assembly of FIG. 6;

FIG. 9 is an enlarged view of an indicated area of detail shown in FIG.8;

FIG. 10 is a perspective view, with parts separated, of the firing camassembly of FIG. 6;

FIG. 11 is a top, perspective view of a staple pusher of the cartridgeassembly of FIG. 5;

FIG. 12 is bottom, perspective view of the staple pusher of FIG. 11;

FIG. 13 is a top, perspective view of a pair of staple pushers of thecartridge assembly of FIG. 5 positioned together, each of the pair ofstaple pushers supporting a pair of staples;

FIG. 14 is an enlarged, cross-sectional view of the cartridge assemblytaken along section line 14-14 illustrated in FIG. 2;

FIG. 15 is a bottom view of the cartridge assembly with T-bars of thecartridge assembly shown in a first position;

FIG. 16 is a bottom, perspective view of the cartridge assembly shown inFIG. 15;

FIG. 17 is an enlarged, bottom, perspective view of portions of thecartridge assembly of FIGS. 15 and 16;

FIG. 18 is an enlarged, bottom view of a proximal portion of thecartridge assembly with portions of the cartridge assembly removedand/or shown in phantom for clarity, the firing assembly shown in afirst proximal position;

FIG. 19 is a side, cross-sectional view of the cartridge assembly withthe firing assembly shown in the first proximal position and the T-barsshown in the first position;

FIG. 20 is an enlarged, cross-sectional view of a distal portion of thecartridge assembly with the firing assembly shown in a first distalposition and with the T-bars shown in a second position;

FIG. 21 is a bottom, perspective view of portions of the cartridgeassembly with the T-bars shown in the second position; and

FIGS. 22 and 23 are bottom views of the proximal portion of thecartridge assembly showing the firing assembly progressing to a secondproximal position.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical stapling apparatus aredescribed in detail with reference to the drawings, in which likereference numerals designate identical or corresponding elements in eachof the several views. As used herein, the term “distal” refers to thatportion of the surgical stapling apparatus, or component(s) thereof,that is farther from the clinician, while the term “proximal” refers tothat portion of the surgical stapling apparatus, or component(s)thereof, that is closer to the clinician.

FIG. 1A illustrates one embodiment of the presently disclosed surgicalstapling apparatus 10. Briefly, surgical stapling apparatus 10 includesa handle assembly 12, an elongated body 14 and a loading unit 100, whichmay be disposable and/or include one or more disposable components.Elongated body 14 and loading unit 100 define a longitudinal axis“X1-X1” that extends longitudinally along elongated body 14. Withreference also to FIGS. 1B, 2, and 3, loading unit 100 is releasablysecured to a distal end of elongated body 14 and includes a toolassembly 110. Tool assembly 110 includes a cartridge assembly 130 thathouses a plurality of staples and an anvil assembly 120 that ispivotally secured to loading unit 100 by a pair of pivot pins 128 a, 128b (FIG. 4) that define a pivot axis “X2-X2.” Anvil assembly 120 isconfigured to pivot about pivot axis “X2-X2” in relation to cartridgeassembly 130, as indicated by arrow “A,” between spaced and approximatedpositions.

Handle assembly 12 includes a stationary handle 16, a movable handle 18and a barrel portion 20. A rotatable member 22 is rotatably supported ona distal end of barrel position 20. Rotatable member 22 supports aproximal end of elongated body 14 and is rotatable in relation to barrelportion 20 of handle assembly 12, as indicated by arrow “B,” toeffectuate rotation of elongated body 14 and tool assembly 110 aboutlongitudinal axis “X1-X1” in relation to handle assembly 12. Rotatablemember 22 supports an articulation lever 24, and barrel portion 20supports a retraction member 26 and a firing release button 28. Handleassembly 12 is described in detail in, for example, U.S. Pat. No.8,070,033 to Milliman et al. (“the '033 patent”), the entire contents ofwhich are incorporated herein by reference.

Elongated body 14 supports a control rod 15 (FIG. 1B) that is coupled toa proximal end of a firing cam assembly 140 (FIG. 4) of loading unit 100as described in further detail below. A release switch 15 a (FIG. 1B) isprovided on rotatable member 22 of handle assembly 12 to facilitatedisengagement of loading unit 100 from elongated body 14.

Referring to FIG. 4, loading unit 100 includes a proximal body portion101 having an upper housing half 102 that is adapted to releasablyengage a distal end of elongated body 14 (FIGS. 1A and 1B) of surgicalstapling apparatus 10 and a lower housing half 104 that couples to upperhousing half 102 of proximal body portion 101. A distal end of upperhousing half 102 defines a recess 102 a that receives a first end of afirst coupling member 103 a and distal end of lower housing half 104defines a recess 104 a that receives a first end of a second couplingmember 103 b. Each coupling member 103 a, 103 b defines an opening 1032therethrough. Upper housing half 102 defines a channel 102 c and lowerhousing half 104 defines a channel 104 b. Together, channels 102 c, 104b slidably receive firing cam assembly 140, as will be described infurther detail below.

Upper housing half 102 has a proximal end that includes engagement nubs102 b. Engagement nubs 102 b are positioned and configured to releasablyengage a distal end of elongated body 14 of handle assembly 12 (FIG. 1)in a bayonet-type coupling arrangement to secure loading unit 100 toelongated body 14. This structure is similar to that described in U.S.Pat. No. 7,780,055 to Scirica et al. (“the'055 patent”) and U.S. Pat.No. 7,143,924 to Scirica et al. (“the'924 patent”), the entire contentsof each of which are incorporated by reference herein.

A pair of blow out plate assemblies 105 a, 105 b is positioned adjacentdistal ends of upper and lower housing halves 102, 104 to preventoutward buckling and/or bulging of firing cam assembly 140 duringarticulation and firing of tool assembly 110. The configuration of theblow out plate assemblies is described in detail, for example, inInternational Publication No. WO/2003/030743, the entire contents ofwhich are incorporated by reference herein.

A locking member 106 is rotatably supported about proximal body portion101. Locking member 106 is movable from a first position engaged withfiring cam assembly 140 to axially lock firing cam assembly 140 to asecond position, unlocking firing cam assembly 140 to enable axialmovement of firing cam assembly 140. Locking member 106 is movable fromthe first position to the second position in response to attachment ofloading unit 100 to surgical stapling apparatus 10. For a more detaileddescription of the construction and operation of locking member 106,reference can be made to the '924 patent, which has been incorporated byreference herein as noted above.

A mounting assembly 107 includes upper and lower mounting portions 107a, 107 b pivotally secured to a distal end of proximal body portion 101and configured to engage and support a proximal end of anvil andcartridge assemblies 120, 130 such that pivotal movement of mountingassembly 107 in relation to proximal body portion 101 effectuatesarticulation of tool assembly 110 in relation to proximal body portion101. Upper mounting portion 107 a includes a central pin 1074 a thatextends upwardly therefrom and lower mounting portion 107 b includes acentral pin 1074 b (FIG. 4) that extends downwardly therefrom. Centralpins 1074 a, 1074 b of upper and lower mounting portions 107 a, 107 bare received within respective openings 1032 of first and secondcoupling members 103 a, 103 b to pivotably couple mounting assembly 107to proximal body portion 101. Upper mounting portion 107 a furtherincludes a pin 1076 that is offset from the longitudinal axis “X1-X1” ofloading unit 100 and lower mounting portion 107 b defines pin channels1078. Both will be described in further detail below.

An articulation link 108 is slidably positioned between upper and lowerhousing halves 102, 104 and defines an opening 108 a. Opening 108 a ofarticulation link 108 receives pin 1076 of upper mounting portion 107 ato facilitate articulation of tool assembly 110 about pins 1074 a and1074 b in relation to proximal body portion 101 of loading unit 100.Pivoting movement of articulation lever 24, as indicated by arrow “CC,”causes axial movement of articulation link 108 along axis “X1-X1” topivot/articulate mounting assembly 107, as indicated by arrow “C,” aboutan axis “X3-X3” (FIG. 1A) of proximal body portion 101 that istransverse to axes “X1-X1” and “X2-X2” (FIG. 1A). For a more detaileddescription of the construction and operation of articulation link 108and mounting assembly 107 reference can be made to the '033 patent,which has been incorporated by reference herein as noted above.

Pins 109 a, 109 b are received through openings 1072 defined in upperand lower mounting portions 107 a, 107 b, to couple upper and lowermounting portions 107 a, 107 b together.

With continued reference to FIG. 4, as discussed above, tool assembly110 includes anvil assembly 120 and cartridge assembly 130 that arepositioned to move in relation to each other between unapproximated andapproximated positions. Anvil assembly 120 is pivotably secured tomounting assembly 107 by pivot pins 128 a, 128 b to enable pivotalmovement of anvil assembly 120 relative to mounting assembly 107 andcartridge assembly 130. Lower mounting portion 107 b includes a distalportion that is secured within support plate 132 of cartridge assembly130 by pivot pins 128 a, 128 b to fixedly secure cartridge assembly 130to mounting assembly 107.

Anvil assembly 120 includes an anvil body 122 and an anvil plate 124that is secured to an underside of anvil body 122. Anvil plate 124includes a tissue contact surface 124 a that defines a plurality ofstaple forming depressions 124 b (FIG. 20). A proximal end of anvil body122 includes a bracket 126 that defines apertures 126 a therethrough.

Turning now to FIG. 5 and FIG. 14, cartridge assembly 130 includes asupport plate 132, a cartridge body 134, a plurality of staple pushers136 including staple pushers 136 a, 136 b, 136 c, 136 d, a pair ofT-bars 138 a, 138 b, and a plurality of staples “S.”

Support plate 132 includes sidewalls 132 a that define a plurality ofwindows 132 b and pin channels 132 c therethrough. An inner surface 132d of support plate 132 defines a channel 132 e that extendslongitudinally along support plate 132 and is adapted to receivecartridge body 134.

Cartridge body 134 includes a tissue contact surface 134 a that definesa plurality of staple retention pockets 134 b arranged in a plurality ofrows “R1”-“R8” extending longitudinally along tissue contact surface 134a. Cartridge body 134 further defines a knife slot 134 d that extendslongitudinally along tissue contact surface 134 a. A plurality of clips134 e extends from a side surface of cartridge body 134. Clips 134 e ofcartridge body 134 are received in the plurality of windows 132 b ofsupport plate 132 to secure cartridge body 134 within channel 132 e ofsupport plate 132 by, for example, snap-fit connection. Other forms ofconnection can be used alternatively and/or additionally to clips 134 eand windows 132 b. A proximal end of cartridge body 134 defineselongated T-bar channels 134 f, 134 g that extend through tissue contactsurface 134 a and a pair of spring channels 134 h, 134 i. ElongatedT-bar channels 134 f, 134 g slidably receive T-bars 138 a, 138 b thereinto enable and limit axial movement of T-bars 138 a, 138 b in relation tocartridge body 134. Spring channels 134 h, 134 i receive a pair of leafsprings 135 a, 135 b therein that are adapted to bias anvil assembly 120to an unapproximated/open position relative to cartridge assembly 130when firing cam assembly 140 is in a proximal position as described ingreater detail below.

Referring also to FIG. 4, pins 128 a, 128 b are received withinapertures 126 a of anvil body 122, pin channels 132 c of support plate132, and pin channels 1078 of lower mounting portion 107 b to couplemounting assembly 107, anvil assembly 120, and cartridge assembly 130together. As described above, pins 128 a, 128 b enable anvil assembly120 to pivot about pivot axis “X2-X2” (FIG. 1A) relative to cartridgeassembly 130 to position anvil and cartridge assemblies 120, 130 betweenunapproximated and approximated positions.

Each of the T-bars 138 a, 138 b includes an elongated shaft 1384 and apost 1382 that extends upwardly from elongated shaft 1384. Elongatedshaft 1384 defines proximal and distal elongated channels 1384 a, 1384 band supports a distally located cross member 1386. Cross member 1386extends outwardly beyond sidewalls of elongated shaft 1384 in adirection transverse to longitudinal axis “X1-X1” of elongated body 14(FIG. 1A) to define a pair of abutments 1386 a, 1386 b.

Referring now to FIGS. 6-10, firing cam assembly 140 includes a first orright hand firing cam 142, a second or left hand firing cam 144, and aknife bar 146 supporting a drive beam 148. Proximal ends of right andleft hand firing cams 142, 144 and knife bar 146 are coupled togetherusing any suitable fastening technique such as tack welding (FIG. 9),for example. Right and left hand firing cams 142, 144 are elongated,resilient, and can flex outwardly from knife bar 146 as indicated byarrows “D” and “E” in FIG. 8.

Right and left hand firing cams 142, 144 are substantially identical andtherefore, in the interest of brevity, only right hand firing cam 142 isdescribed in detail. A proximal end of right hand firing cam 142includes first and second spaced arms 142 a, 142 b that define anopening 142 c. First and second arms 142 a, 142 b extend distally fromthe proximal end and are joined to an elongated shaft portion 142 d.Elongated shaft 142 d extends distally from first and second arms 142 a,142 b to a driver head 142 e. Right and left hand firing cams 142, 144are configured to have a narrow profile, for example, to enable smoothtranslation through firing channels 137 a-137 d defined in cartridgebody 134.

As seen in FIG. 7, a bottom surface of driver head 142 e of each ofright and left hand firing cams 142, 144, respectively, includes a rib142 f and a top surface of driver head 142 e defines a cam surface 142g. A distal end of rib 142 f defines a shoulder 142 h that is positionedbeneath a tip portion 142 i of cam surface 142 g.

With reference to FIGS. 9 and 10, knife bar 146 includes resilient bars146 a, 146 b, 146 c, 146 d that are substantially identical. A proximalend of each bar of the plurality of bars 146 a, 146 b, 146 c, 146 dincludes first and second spaced arms 1462, 1464 that define an opening1466 open at its proximal end. Opening 1466 is positioned to receivecontrol rod 15 of surgical stapling apparatus 10 when loading unit 100is coupled to elongated body 14 of surgical stapling apparatus 10. Firstand second arms 1462, 1464 are secured together by one or more posts1468 a, 1468 b.

With reference again to FIG. 7, drive beam 148 is secured to a distalend of knife bar 146 and has an I-shaped cross-sectional profile. Drivebeam 148 includes a lower retention foot 148 a, an upper retention foot148 b, and a vertically-oriented support strut 148 c that couples lowerand upper retention feet 148 a, 148 b together. Vertically-orientedsupport strut 148 c supports a blade 148 d with a sharpened edge adaptedto sever tissue. Drive beam 148 is positioned between right and lefthand firing cams 142, 144 and disposed proximal of driver heads 142 e ofright and left hand firing cams 142, 144.

With reference to FIGS. 11-14, staple pushers 136 are substantiallysimilar in that each staple pusher of the plurality of staple pushers136 includes a first pusher plate 1362, a second pusher plate 1364, anda cam member 1366 that connects first and second pusher plates 1362,1364 together. First and second pusher plates 1362, 1364 arelongitudinally offset and each defines a staple support channel 1363that is configured to support a backspan of one of the staples “S.” Cammember 1366 includes a pusher ramp 1368 that is adapted to engage camsurface 142 g of one of right and left hand firing cam members 142, 144.

Staple pushers 136 are arranged in cartridge body 134 on each side ofknife slot 134 d such that staple pushers 136 are disposed inregistration with corresponding rows of staple retaining pockets 134 bof cartridge body 134 (e.g., rows “R1”-“R8” seen in FIG. 5) (four rowson either side of knife slot 134 d). Each staple pusher 136 isassociated with two of the four rows on one of the two sides of knifeslot 134 d of cartridge body 134.

Staple pushers from adjacent rows of staple pushers within cartridgebody 134 are disposed in a nested relationship to support staples “S” infour adjacent rows (e.g., rows “R1”-“R4”) on each side of knife slot 134d. In the nested relationship, staple pushers 136 a, 136 b (FIG. 13)include cam members 1366 a, 1366 b disposed in mirrored relationshipsuch that first pusher plate 1362 of staple pusher 136 a islongitudinally aligned with second pusher plate 1364 of staple pusher136 b, and second pusher plate 1364 of staple pusher 136 a islongitudinally aligned with first pusher plate 1362 of staple pusher 136b.

Referring to FIGS. 15-18, cartridge body 134 further defines a pluralityof firing channels 137 a-137 d. Firing channels 137 a and 137 c areadapted to receive right hand firing cam 142 and firing channels 137 b,137 d are adapted to receive left hand firing cam 144. Firing assembly140 is preloaded within cartridge body 134 in a first proximal position.In the first proximal position, resilient right hand firing cam 142 isdisposed in an outwardly deformed orientation against its natural biaswith drive head 142 e of right hand firing cam 142 positioned withinfiring channel 137 a. Also in the first proximal position, left handfiring cam 144 is disposed in an inwardly deformed orientation againstits natural bias with drive head 142 e of left hand firing cam 144positioned within firing channel 137 d.

T-bars 138 a, 138 b are movable from a proximal or retracted positionwithin cartridge body 134 to a distal or advanced position. In theproximal position, the proximal end of T-bars 138 a and 138 b arepositioned to retain right and left hand firing cams 142 and 144,respectively, within firing channels 137 a and 137 d, respectively. Morespecifically, side surfaces of T-bars 138 a, 138 b engage side surfacesof right and left hand firing cams 142, 144 to prevent right and lefthand firing cams 142, 144 from moving toward their non-deformedorientation when right and left hand firing cams 142, 144 and T-bars 138a, 138 b are fully retracted (see FIGS. 22-23).

Cartridge body 134 also includes ramps 139 that are positioned to engageright and left hand firing cams 142, 144 during first and/or secondaxial translations of firing cam assembly 140 within cartridge body 134,as described in greater detail below. The plurality of ramps 139includes a first ramp 139 a that is configured to direct drive head 142e of right hand firing cam 142 into firing channel 137 c so that drivehead 142 e of right hand firing cam 142 is positioned to axiallytranslate along firing channel 137 c. A second ramp 139 b of theplurality of ramps 139 directs drive head 142 e of left hand firing cam144 within firing channel 137 b so that drive head 142 e of left handfiring cam 144 is positioned to axially translate along firing channel137 b. First ramp 139 a is shown with a rounded bump and second ramp 139b is shown with a flat, shallow slope, but one or both of these ramps139 a, 139 b may include any suitable shape and/or dimension tofacilitate movement of right and left hand firing cams 142, 144 into theappropriate firing channels.

Cartridge body 134 includes proximal and distal T-bar engagement posts131 a, 131 b and defines a T-bar recess 133 dimensioned to receive adistal portion of T-bars 138 a, 139 b. Proximal and distal T-barengagement posts 131 a, 131 b are received within proximal and distalelongated channels 1384 a, 1384 b of T-bars 138 a, 138 b, respectively,to maintain alignment of T-bars 138 a, 138 b as T-bars 138 a, 138 btranslate relative to cartridge body 134, as described in greater detailbelow. Engagement surfaces 133 a (FIG. 15) extend from cartridge body134 into T-bar recess 133. Engagement surfaces 133 a are adapted tofrictionally engage cross members 1386 of T-bars 138 a, 138 b tomaintain T-bars 138 a, 138 b in an advanced position relative tocartridge body 134 when T-bars 138 a, 138 b are received within T-barrecess 133. The pair of engagement surfaces 133 a can have any suitableshape/dimension (e.g., rounded, tapered, etc.) and/or may includesurface texturing (e.g., bumps knurling, ribs, etc.).

In use, as illustrated in FIGS. 1A and 18-23, firing cam assembly 140 isactuated (e.g., via pivotal retraction of movable handle 18 of handleassembly 12, as indicated by arrow “AA”) to advance drive beam 148 andright and left hand firing cams 142, 144 distally through cartridge body134 as indicated by arrow “F.” As drive beam 148 advances distallythrough cartridge body 134, upper and lower retention feet 148 a, 148 bare received within channels (not shown) defined within anvil andcartridge assemblies 120, 130 to approximate anvil and cartridgeassemblies 120, 130 while blade 148 d (FIG. 7) advances through knifeslot 134 d to severe tissue grasped between anvil and cartridgeassemblies 120, 130. With drive beam 148 advancing through cartridgebody 134, right and left hand firing cams 142, 144 simultaneouslydistally translate through firing channels 137 a, 137 d, respectively,so that cam surfaces 142 g of right and left hand firing cams 142, 144engage pusher ramps 1368 of the plurality of staple pushers 136 during afirst axial translation of firing cam assembly 140 to fire staples “S”of rows “R2,” “R4,” “R6,” and “R8” and to form the fired staples withincorresponding staple forming depressions 124 b of anvil assembly 120.

Just before right and left hand firing cams 142, 144 reach a distal-mostposition, shoulders 142 h of drive heads 142 e of right and left handfiring cams 142, 144 engage one of the pair of abutments 1386 a, 1386 bof cross members 1386 of T-bars 138 a, 138 b, respectively. Withproximal and distal T-bar engagement posts 131 a, 131 b of cartridgebody 134 maintaining lateral alignment of T-bars 138 a, 138 b withincartridge body 134, posts 1382 of T-bars 138 a, 138 b distally translatethrough T-bar channels 134 f, 134 g of cartridge body 134 as right andleft hand firing cams 138 a, 138 b engage and drive first and secondT-bars 138 a, 138 b distally to a distal-most position relative tocartridge body 134. In the distal-most position, the distal portions ofT-bars 138 a, 138 b are received within T-bar recess 133 of cartridgebody 134 and maintained therein via frictional engagement with the pairof engagement surfaces 133 a of cartridge body 134 (see FIG. 21).

Referring to FIGS. 22-23, with T-bars 138 a, 138 b fixed in thedistal-most position, firing cam assembly 140 can then be retractedproximally to a second proximal position, as indicated by arrows “G,”(e.g., via retraction of retraction member 26 of handle assembly 12 inthe proximal direction, as indicated by arrow “AAA” in FIG. 1A).Retraction of firing cam assembly 140 moves drive beam 138 proximallyand unapproximates anvil and cartridge assemblies 120, 130. When firingcam assembly 140 is retracted to its second proximal position, driveheads 142 e of right and left hand firing cams 142, 144 are disposedproximal to proximal ends of T-bars 138 a, 138 b. Since drive heads 142e no longer engage the proximal end of T-bars 138 a, 138 b, drive heads142 e of right and left hand firing cams 142, 144 move/pivot towardtheir natural, unflexed orientation, as indicated by arrows “H” andsprings 135 a, 135 b (FIG. 5) spring bias anvil assembly 120 open. Inthe natural, unflexed orientations of right and left hand firing cams142, 144, drive heads 142 e of right and left hand firing cams 142, 144are aligned with firing channels 137 b, 137 c of cartridge body 134,respectively. First ramp 139 a of cartridge body 134 directs right handfiring cam 142 into firing channel 137 c of cartridge body 134 andsecond ramp 139 b directs left hand firing cam 144 into firing channel137 b. Firing cam assembly 140 can then again be distally advanced, asindicated by arrow “F,” to fire loading unit 100 a second time. Surgicalstapling apparatus 10 can be released from tissue after the first firingand re-positioned to clamp tissue at a different location before thesecond firing.

During a second axial translation of firing cam assembly 140, drive beam148 again advances distally through cartridge body 134 so that upper andlower retention feet 148 a, 148 b of drive beam 148 approximate anviland cartridge assemblies 120, 130. With drive beam 148 advancingdistally through cartridge body 134, right and left hand firing cams142, 144 simultaneously distally translate through firing channels 137c, 137 b, respectively, so that cam surfaces 142 g of right and lefthand firing cams 142, 144 engage pusher ramps 1368 of the plurality ofstaple pushers 136 during a first axial translation of firing camassembly 140 to fire staples “S” of rows “R1,” “R3,” “R5,” and “R7” andto form the fired staples within corresponding staple formingdepressions 124 b of anvil assembly 120.

Loading unit 100 and/or cartridge assembly 130 can be removed and/orreplaced with a new loading unit 100 and/or a new cartridge assembly 130as desired.

Persons skilled in the art will understand that the structures andmethods specifically described herein and shown in the accompanyingfigures are non-limiting exemplary embodiments, and that thedescription, disclosure, and figures should be construed merely asexemplary of particular embodiments. It is to be understood, therefore,that the present disclosure is not limited to the precise embodimentsdescribed, and that various other changes and modifications may beeffected by one skilled in the art without departing from the scope orspirit of the disclosure. Additionally, the elements and features shownor described in connection with certain embodiments may be combined withthe elements and features of certain other embodiments without departingfrom the scope of the present disclosure, and that such modificationsand variations are also included within the scope of the presentdisclosure. Accordingly, the subject matter of the present disclosure isnot limited by what has been particularly shown and described.

1.-20. (canceled)
 21. A tool assembly comprising: a cartridge bodydefining a first firing channel and a second firing channel, the firstfiring channel associated with a first row of staples and the secondfiring channel associated with a second row of staples; and a firstfiring cam positioned within the first firing channel of the cartridgebody, the first firing cam configured to translate through the firstfiring channel during a first axial translation of the first firing camto fire the first row of staples, the first firing cam being biased tomove into the second firing channel of the cartridge body uponretraction of the first firing cam after the first axial translationsuch that the first firing cam moves to a position to translate throughthe second firing channel upon a second axial translation of the firstfiring cam to fire the second row of staples.
 22. The tool assembly ofclaim 21, wherein the first firing cam is engaged with a first T-bar,the first T-bar is positioned to maintain the first firing cam inregistration with the first firing channel when the first firing cam andthe first T-bar are in fully retracted positions.
 23. The tool assemblyof claim 22, further including a second firing cam, the cartridge bodydefining third and fourth firing channels, the second firing camconfigured to translate through the third firing channel during thefirst axial translation to fire a third row of staples, the secondfiring cam being biased to move into the fourth firing channel uponretraction of the second firing cam after the first axial translationsuch that the second firing cam is positioned to translate through thefourth firing channel upon the second axial translation to fire a fourthrow of staples.
 24. The tool assembly of claim 23, wherein the secondfiring cam is engaged with a second T-bar, the second T-bar positionedto maintain the second firing cam in registration with the third firingchannel when the second firing cam and the second T-bar are in fullyretracted positions.
 25. The tool assembly of claim 24, wherein thefirst and second T-bars are configured to move along the cartridge bodyin response to movement of the first and second firing cams from aproximal position to a distal position during the first axialtranslation, the first and second T-bars being retained in the distalposition as the first and firing cams are retracted to the proximalposition after the first axial translation, wherein in the distalposition, the first and second T-bars are positioned to enable movementof the first and second firing cams.
 26. The tool assembly of claim 25,wherein the cartridge body defines a T-bar recess, the first and secondT-bars being positioned within the T-bar recess while the first andsecond T-bars are disposed in the distal position.
 27. The tool assemblyof claim 23, wherein the first and second firing cams are pivotallycoupled together and positioned to pivot relative to one another. 28.The tool assembly of claim 23, wherein the cartridge body includes afirst ramp and a second ramp, the first ramp positioned to align thefirst firing cam with one of the first and second firing channels, thesecond ramp positioned to align the second firing cam with one of thethird and fourth firing channels.
 29. The tool assembly of claim 21,further including a knife bar that supports a blade at a distal end ofthe knife bar, the cartridge body defining a knife channel, the knifebar being distally movable through the knife channel as the first firingcam translates through the first and second firing channels.
 30. Thetool assembly of claim 29, wherein the first firing cam includes a camsurface positioned to engage a plurality of pusher members, each of theplurality of pusher members configured to support at least one of thestaples.
 31. The tool assembly of claim 30, wherein the cam surface ofthe first firing cam extends distally beyond the blade of the knife bar.32. The tool assembly of claim 23, wherein the cartridge body defines aknife channel therethrough, wherein two of the first, second, third, andfourth firing channels are disposed on one side of the knife channel andwherein a remaining two of the first, second, third and fourth firingchannels are disposed on another side of the knife channel.
 33. Asurgical stapling device comprising: a housing; a shaft that extendsdistally from the housing; and a tool assembly supported on the shaft,the tool assembly including: a cartridge body defining a first firingchannel and a second firing channel, the first firing channel associatedwith a first row of staples and the second firing channel associatedwith a second row of staples; and a first firing cam positioned withinthe first firing channel of the cartridge body, the first firing camconfigured to translate through the first firing channel during a firstaxial translation of the first firing cam to fire the first row ofstaples, the first firing cam being biased to move into the secondfiring channel of the cartridge body upon retraction of the first firingcam after the first axial translation such that the first firing cammoves to a position to translate through the second firing channel upona second axial translation of the first firing cam to fire the secondrow of staples.
 34. The surgical stapling device of claim 33, whereinthe first firing cam is engaged with a first T-bar, the first T-barpositioned to maintain the first firing cam in registration with thefirst firing channel when the first firing cam and the first T-bar arein fully retracted positions.
 35. The surgical stapling device of claim34, further including a second firing cam, the cartridge body definingthird and fourth firing channels, the second firing cam configured totranslate through the third firing channel during the first axialtranslation to fire a third row of staples, the second firing cam beingbiased to move into the fourth firing channel upon retraction of thesecond firing cam after the first axial translation such that the secondfiring cam is positioned to translate through the fourth firing channelupon the second axial translation to fire a fourth row of staples. 36.The surgical stapling device of claim 35, wherein the second firing camis engaged with a second T-bar, the second T-bar positioned to maintainthe second firing cam in registration with the third firing channel whenthe second firing cam and the second T-bar are in fully retractedpositions.
 37. The surgical stapling device of claim 36, wherein thefirst and second T-bars are configured to move along the cartridge bodyin response to movement of the first and second firing cams from aproximal position to a distal position during the first axialtranslation, the first and second T-bars being retained in the distalposition as the first and firing cams are retracted to the proximalposition after the first axial translation, wherein in the distalposition, the first and second T-bars are positioned to enable movementof the first and second firing cams.
 38. The surgical stapling device ofclaim 37, wherein the cartridge body defines a T-bar recess, the firstand second T-bars being positioned within the T-bar recess while thefirst and second T-bars are disposed in the distal position.
 39. Thesurgical stapling device of claim 35, wherein the cartridge bodyincludes a first ramp and a second ramp, the first ramp positioned toalign the first firing cam with one of the first and second firingchannels, the second ramp positioned to align the second firing cam withone of the third and fourth firing channels.
 40. The surgical staplingdevice of claim 34, further including a knife bar supporting a blade ata distal end of the knife bar, the cartridge body defining a knifechannel, the knife bar being distally movable through the knife channelas the first firing cam translates through the first and second firingchannels.